title: Enantioconvergent biohydrolysis of racemic styrene oxide to R-phenyl-1, 2-ethanediol by a newly isolated filamentous fungus Aspergillus tubingensis TF1.
abstract: An effort was made to isolate biocatalysts hydrolyzing epoxides from various ecological niches of northeast India, a biodiversity hot spot zone of the world and screened for epoxide hydrolase activity to convert different racemic epoxides to the corresponding 1, 2-vicinal diols. Screening of a total of 450 microorganisms isolated was carried out using NBP colorimetric assay. One of the strains TF1, after internal transcribed spacer sequence analysis, identified as Aspergillus tubingensis, showed promising enantioconvergent epoxide hydrolase activity. The hydrolysis of unsubstituted styrene oxide (1) occurred to give 97 % ee of R-(-)-1-phenylethane-1, 2-diol (6) with more than 99 % conversion within 45 min incubation. It is shown to be a cheap and practical biocatalyst for one step asymmetric synthesis of chiral R-diol. The other representative substrates (2-5), although underwent hydrolysis with more than 99 % conversion beyond 15 h, exhibited poor enantioselectivity.
authors.affiliation: CSIR-North East Institute of Science & Technology, Jorhat, 785006, Assam, India.
authors.forename: Aparajita
authors.initials: A
authors.lastname: Duarah
authors.forename: Amrit
authors.initials: A
authors.lastname: Goswami
authors.forename: Tarun C
authors.initials: TC
authors.lastname: Bora
authors.forename: Madhumita
authors.initials: M
authors.lastname: Talukdar
authors.forename: Binod K
authors.initials: BK
authors.lastname: Gogoi
mesh_terms: D001230:Aspergillus / Q000145:classification* / Q000302:isolation & purification / Q000378:metabolism*; D004851:Epoxide Hydrolases / Q000378:metabolism*; D004852:Epoxy Compounds / Q000378:metabolism*; D005026:Ethylene Glycols / Q000138:chemical synthesis*; D006868:Hydrolysis; D007536:Isomerism; D013045:Species Specificity
chemical_list: D004852:Epoxy Compounds; D005026:Ethylene Glycols; C031474:styrene glycol; C013690:styrene oxide; D004851:Epoxide Hydrolases